108 ASPARAGUS 
nels between the rows for conducting the steam. ‘To 
guard against the steam’s escaping, two or three 
inches of soil was placed over the boards, and the 
asparagus patch was then covered with five or six 
inches of horse manure. This covering was to prevent 
the heat from escaping from the soil too rapidly. It 
was then ready for the steam to be turned into the 
tunnels. 
‘“’To conduct the steam a one and one-half inch 
pipe was carried above ground from the boiler to one 
end of the central tunnel, a distance of one hundred 
and eighty-five feet. A steam hose long enough to 
reach each tunnel was attached to this pipe through 
which to blow steam into the tunnels. It was not the 
idea to give a constant supply of steam, but to dis- 
charge a little into the tunnels each afternoon, or as 
often as was necessary to maintain sufficient warmth. 
A piece of tile was inserted into the mouth of each 
tunnel to prevent the discharging steam from tearing 
away the earth. 
‘The first steam was turned into the tunnels on 
November 14th. Steam was discharged into each 
tunnel, not to exceed five minutes at a time, in order 
not to heat the earth too hot in any single place. It 
required about one hour of steaming the first day to 
bring the bed up to the required temperature of sixty 
degrees. The distribution of heat throughout the 
bed was very uniform and satisfactory. The moist 
steam seemed to permeate the soil equally in all 
directions. 
‘« After the first day very little steaming was neces- 
sary until the asparagus began to be produced. On 
